[英]Hamburger Icon not opening Navigation Drawer on parent fragment after returning from child fragment by clicking back arrow on toolbar
我正在構建的應用程序使用導航抽屜android.support.v4.widget.DrawerLayout
和MainActivity
擴展了android.support.v7.app.AppCompatActivity
。 我有一個被子片段替換的父片段。 在父片段上,默認漢堡包圖標正確切換了導航抽屜。 在子片段上時,使用此代碼段將漢堡包圖標替換為后退箭頭圖標
((MainActivity)getActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(true);
toolbar = (Toolbar) (getActivity()).findViewById(R.id.toolbar);
((MainActivity)getActivity()).setSupportActionBar(toolbar);
在子片段上,后退按鈕的單擊事件在onOptionsItemSelected()
上處理,並且在onStop()
上再次顯示父片段的漢堡圖標。
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
getActivity().onBackPressed();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
@Override
public void onStop() {
super.onStop();
((MainActivity)getActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(false);
MainActivity.toggle.syncState();
}
現在,在父片段上的漢堡包圖標可以正確顯示,但是單擊它后,導航抽屜將不再顯示。
有人可以幫我做錯什么嗎?
以下是相關文件:
MainActivity.java
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
public static ActionBarDrawerToggle toggle;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
try {
Fragment fragment = (Fragment) ParentFragment.class.newInstance();
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_content, fragment).commit();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
}
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
}
activity_main.xml中
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:openDrawer="start">
<include
layout="@layout/app_bar_main"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<android.support.design.widget.NavigationView
android:id="@+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="true"
app:headerLayout="@layout/nav_header_main"
app:menu="@menu/activity_main_drawer" />
</android.support.v4.widget.DrawerLayout>
ParentFragment.java
public class ParentFragment extends Fragment implements View.OnClickListener {
public static ParentFragment newInstance() {
ParentFragment fragment = new ParentFragment();
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
}
@Override
public void onClick(View v) {
int i = v.getId();
Fragment fragment = null;
if(i == R.id.child_fragment_button) {
fragment = new ChildFragment();
}
if(fragment != null) {
FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.fragment_content, fragment)
.addToBackStack(null)
.commit();
}
}
}
ChildFragment.java
public class ChildFragment extends Fragment {
private Toolbar toolbar;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
// Show back button
((MainActivity)getActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(true);
toolbar = (Toolbar) (getActivity()).findViewById(R.id.toolbar);
((MainActivity)getActivity()).setSupportActionBar(toolbar);
}
@Override
public void onStop() {
super.onStop();
((MainActivity)getActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(false);
MainActivity.toggle.syncState();
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
getActivity().onBackPressed();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
}
我終於想出了解決方案。 感謝這個答案 。
這是我所做的更改:
ChildFragment.java
public class ChildFragment extends Fragment {
private Toolbar toolbar;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
// Show back button
toggle = MainActivity.toggle;
toggle.setDrawerIndicatorEnabled(false);
toggle.setToolbarNavigationClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
FragmentManager manager = getActivity().getSupportFragmentManager();
manager.popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
toggle.setDrawerIndicatorEnabled(true);
}
});
toolbar = (Toolbar) (getActivity()).findViewById(R.id.toolbar);
toolbar.setNavigationIcon(((MainActivity)getActivity()).getDrawerToggleDelegate().getThemeUpIndicator());
}
@Override
public void onStop() {
super.onStop();
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
default:
return super.onOptionsItemSelected(item);
}
}
}
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